Heat exchanger with concentric flow passageways



June 15, 1965 L. H. ESSER ETAL 3,189,086

HEAT EXCHANGER WITH CONCENTRIC FLOW PASSAGEWAYS Filed Dec. 31, 1962 2Sheets-Sheet l INVINTORS LU W/G HUBEBT 5552 y ALA/V JAMES WHITE ATTOE/VE VS HEAT EXCHANGER WITH CONCENTRIC FLOW PASSAGEWAYS Filed Dec'.51, 1962 2 Sheets-Sheet 2 2 'INVEA-ITORS LUDW/G HUBEQT 55512 By ALANJAMES WH/TE @WMWW A TTOEN E VS United States Patent On ice 3,189,086Patented June 15, 1965 3,189,086 HEAT EXCHANGER WITH CONCENTRIC FLOWPASSAGEWAYS Ludwig Hubert Esser, Upton Park, London, and Alan JamesWhite, Hayes, England, assignors to Metallurgical Engineers LimitedFiled Dec. 31, 1962, Ser. No. 248,348

Claims priority, applications/(gem Britain, Jan. 2, 1962, 2 Claims. (Cl.165-75) The invention relates to heat exchangers and has among itsobjects to provide maximum heat transference and high efliciency.

According to the invention there is provided a structure for effectingheat exchange between gases in which the gas to be heated is passedthrough a first channel which is heated by heated gas flowing in twoother channels on each side of said first channel.

According to the invention moreover, a heat exchanger comprisesessentially three concentric cylinders mounted to present three adjacentchannels, the heating gases being directed through the outermost andinnermost channels and the gas to be heated through a channel betweenthe other two channels. I

According to the invention furthermore, a heat exchanger is formed as anupstanding cylindrical casing closed at the top and having a lining ofrefractory material, outer and inner cylindrical sleeves of largediameter concentrically mounted, and positioned to present a narrowannular space between the inner surface of the refractory lining and theouter cylindricalsleeve, and a narrow annular space between the outerand inner cylindrical sleeves, the heating gas, such as flue gas,passing upwardly through the inner cylindrical sleeve and downwardlythrough the annular space between the outer cylindrical sleeve and therefractory lining, and the gas to be heated passing upwardly through thenarrow annular space between the outer and inner cylindrical sleeves.

Access to the inner cylindrical member to effect repairs can easily beobtained by removing the lid closing the top of the heat exchanger.

Thus in the construction according to the invention the heat transfer iseffected primarily by convection between the outer cylindrical shell andthe surrounding refractory wall and by radiation between the hot gas andthe inner shell. The overall efficiency of the heat exchanger istherefore higher than in known heat exchangers.

According to the invention furthermore, the gas to be heated passes fromthe annular space between the outer and inner cylindrical sleeves to alateral outlet provided at or near the top of the heatexchanger througha series of radial ports bridging the annular space between the outercylindrical sleeve and the refractory lining and providing communicationbetween the annular space between the outer and inner cylindricalsleeves and an an nular collecting box in communication with the lateraloutlet, the downward flow of the heating gases taking place throughintermediate vertical passages provided between the ports.

According to the invention furthermore, the outer and inner cylindricalsleeves are supported by and secured to, as by welding, a flanged ringsecured to the outer casing of the heat exchanger.

According to the invention furthermore, the radial ports may be formedof a tapering cross-section from top to bottom, to streamline the flowof heating gas past the ports.

The invention further comprises the features of construction hereinafterdescribed.

The invention is diagrammatically and non-limitatively illustrated byway of example in the accompanying drawings, in which:

FIGURE 1 is a sectional elevation of a heat exchanger constructedaccording to the invention, and

FIGURE 2 is a sectional elevation on. an enlarged scale of the top partof the heat exchanger.

In carrying the invention into effect as illustrated in the drawings,the heat exchanger may comprise an up standing outer metal casing 1closed by a domed cap 3 and having a lining 2 of a refractory material,a lateral outlet 4 for the heated gas is provided at the upper part anda lateral inlet 5 for the gas to be heated is provided at the lower partof the heat exchanger. At or near the bottom of the heat exchanger isalso provided an outlet 6 for the heating gas. Mounted within the casing1 are two concentric cylindrical sleeves 7 and 8 spaced a short distanceapart, the outer cylinder or sleeve being spaced apart from the innersurface of the refractory lining 2 of the heat exchanger. The twoannular spaces so formed provide passages for the flow of the heatinggases and cold gases to be heated.

The gas to be heated enters the annular space between V the outer andinner cylindrical sleeves through the inlet 5 and passes upwardly to bedischarged through radial ports 9 into an annular chamber 10 and thencethrough the lateral outlet 4 provided in the refractory lining of theheat exchanger.

In a typical heat exchanger taken, for example, and without in any waylimiting the scope of the invention as claimed, the overall height ofthe cylindrical shells may be 24 feet; the diameter of the centralchannel between 3 feet 6 inches and 4 feet 9 inches; the width of theoutermost annular channel 2 inches and the width of the intermediateannular channel for the gas to be heated inch to 1 inch. If such a heatexchanger were supplied with heating gas 'at 1150 C. at a rate of260,000

cubic feet/hour it would heat 130,000 cubic feet/hour the heatexchanger.

of gas from ambient temperature up to 750 C. 7

The heating gas, such as flue gas, enters centrally through the bottomof the heat exchanger, the direction of flow of the gas being reversedat the upper end to cause the fine gasesto pass downwardly throughvertical passages between the radial ports 9, through the annular spacebetween the outer cylindrical sleeve 7 and the inner wall of therefractory lining 2, into an annular chamber 11, and thence to pass outlaterally through an outlet 6 provided near the bottom of the heatexchanger.

The cylindrical sleeves 7 and 8 are supported by a flanged ring 12 whichis welded to the ports 9 and secured to the outer casing 1. An annularring 13 of heat-insulating materal and of substantiallytriangularsection is secured to the casing 1 to prevent the heated gasfrom overheating the joint between the outer casing and the domed top.

A heat expansion/ contraction joint comprising flexible bellows 14 isprovided in the upper end of the heat exchanger for providing a sealbetween the heated gas outlot and the annular space'adjacent therefractory wall of Similarly at the lower end of the heat exchangermeans are provided to provide a seal between the two annuli, such meanstaking the form of flexible bellows 15 appropriately mounted.

The radial ports 9 may be formed to a tapering crosssection from top tobottom as illustrated in FIGURE 2 of the accompanying drawings, wherebythe downward flow of heating gas past the ports 9 is streamlined.

We claim:

1. A heat exchanger, comprising:

an upstanding cylindrical casing having a lining of refractorymate-rial, said casing having a first inlet communicating with thebottom thereof;

a cap removably closing the upper end of said casing;

outer and inner cylindrical sleeves of large diameter mountedconcentrically and spaced a short distance apart to provide a narrowfirst annular space therebetween, said sleeves being positioned withinsaid casing with said outer sleeve being spaced from the inner sunfaceof said lining to provide a second annular space therebetween, the firstannular space being closed at the top and open at the bottom, meansforming a passage between the interior of the inner sleeve and thesecond annular space at the upper end of the casing, said inner sleeveextending to the bottom of said casing for communication with said firstinlet whereby a heated fluid supplied through said first inlet flowsupwardly through said inner sleeve and then downwardly through saidsecond annular space;

means defining a first outlet from said casing adjacent the lower end ofsaid second annular space whereby said heated fluid flowing through saidsecond annular space can be discharged;

means defining a second inlet in said casing communicating with thelower end of said first annular space and isolated from said first inletand said first outlet whereby a fluid to be heated can be supplied tosaid first annular space;

means defining a second outlet extending laterally through said casingand communicating with the upper end of said first annular space wherebythe fluid to be heated can be discharged from the casing;

a plurality of tubular members secured to and penetrating the outersleeve at the upper end thereof and extending laterally therefrom;

a flanged ring secured to said tubular members and including a portionwhich extends outwardly and upwardly to be secured between the cap andthe casing whereby the sleeves are supported on the casing and thesleeves can be removed from the casing when the cap is removed; and

a ring of heat insulation material of substantially triangularcross-section disposed between said lining and said portion of saidflanged ring above said tubular members to prevent overheating of thejoint between the casing and the cap.

2. A heat exchanger, comprising:

an upstanding cylindrical casing having a lining of refractory material,said casing having a first inlet communicating with the bottom thereof;

a cap removably closing the upper end of said casing;

outer and inner cylindrical sleeves of large diameter mountedconcentrically and spaced a short distance apart to provide a narrowfirst annular space therebetween, said sleeves being positioned withinsaid casing with said outer sleeve being spaced from the inner surfaceof said lining to provide a second annular space therebetween, the firstannular space being closed at the top and open at the bottom, meansforming a passage between the interior of the inner sleeve and thesecond annular space at the upper end of the casing, said inner sleeveextending to the bottom of said casing for communication with said firstinlet whereby a heated fluid supplied through said first inlet flowsupwardly through said inner sleeve and then downwardly through saidsecond annular space;

means defining a first outlet from said casing adjacent the lower end ofsaid second annular space whereby said heated fluid flowing through saidsecond annular space can be discharged;

means defining a second inlet in said casing communicating with thelower end of said first annular space and isolated from said first inletand said first outlet whereby a fluid to be heated can be supplied tosaid first annular space;

means defining a second outlet from said casing at the upper endthereof;

said casing forming an annular chamber at its upper end communicatingwith said second outlet whereby fluid entering said annular chamber canflow into said second outlet;

a plurality of circumferentially spaced tubular members secured to andpenetrating said outer sleeve at the upper end thereof and extendingradially outwardly therefrom through said second annular space into saidannular chamber and being in fluid communication with said annularchamber whereby fluid flowing through said first annular space can exittherefrom into said annular chamber and thence into said second outlet,said tubular members each having a cross-section which tapers in adownward direction to streamline the fiow of heated fluid therepast;

wall means for isolating said annular chamber from said second annularspace, said wall means including a flanged ring secured to said tubularmembers, said ring having a portion which extends upwardly and outwardlyto the upper end of the casing whereby said tubular members and saidsleeves are supported on said casing;

the flanged ring extending between said cap and said casing whereby saidsleeves and said tubular members can be removed from said casing whensaid cap is removed.

References Cited by the Examiner UNITED STATES PATENTS 2,372,079 3/45Gunter 165---l41 2,662,749 12/53 Buschow 165141 2,828,946 4/58 Smithl167 2,942,855 6/60 Wellensiek 135 2,991,981 7/61 Andersen 165-141FOREIGN PATENTS 23,336 10/04 Great Britain. 479,736 2/38 Great Britain.595,177 9/25 France. 1,059,689 11/53 France.

7,980 1/23 Netherlands.

CHARLES SUKALO, Primary Examiner.

PERCY L. PATRICK, Examiner.

1. A HEAT EXCHANGER, COMPRISING: AN UPSTANDING CYLINDRICAL CASING HAVINGA LINING OF REFRACTORY MATERIAL, SAID CASING HAVING A FIRST INLETCOMMUNICATING WITH THE BOTTOM THEREOF; A CAP REMOVABLY CLOSING THE UPPEREND OF SAID CASING; OUTER AND INNER CYLINDRICAL SLEEVES OF LARGEDIAMETER MOUNTED CONCENTRICALLY AND SPACED A SHORT DISTANCE APART TOPROVIDE A NARROW FIRST ANNULAR SPACE THEREBETWEEN, SAID SLEEVES BEINGPOSITIONED WITHIN SAID CASING WITH SAID OUTER SLEEVE BEING SPACED FROMTHE INNER SURFACE OF SAID LINEAR TO PROVIDE A SECOND ANNULAR SPACETHEREBTWEEN, THE FIRST ANNULAR SPACE BEING CLOSED AT THE TOP AND OPEN ATTHE BOTTOM, MEANS FORMING A PASSAGE BETWEEN THE INTERIOR OF THE INNERSLEEVE AND THE SECOND ANNULAR SPACE AT THE UPPER END OF THE CASING, SAIDINNER SLEEVE EXTENDING TO THE BOTTOM OF SAID CASING FOR COMMUNICATINGWITH SAID FIRST INLET WHEREBY A HEATED FLUID SUPPLIED THROUGH SAID FIRSTINLET FLOWS UPWARDLY THROUGH SAID SECOND SLEEVE AND THEN DOWNWARDLYTHROUGH SAID SECOND ANNULAR SPACE; MEANS DEFINING A FIRST OUTLET FROMSAID CASING ADJACENT THE LOWER END OF SAID SECOND ANNULAR SPACE WHEREBYSAID HEATED FLUID FLOWING THROUGH SAID SECOND ANNULAR SPACE CAN BEDISCHARGED; MEANS DEFINING A SECOND INLET IN SAID CASING COMMUNICATINGWITH THE LOWER END OF SAID FIRST ANNULAR SPACE AND ISOLATED FROM SAIDFIRST INLET AND SAID FIRST OUTLET WHEREBY A FLUID TO BE HEATED CAN BESUPPLIED TO SAID FIRST ANNULAR SPACE; MEANS DEFINING A SECOND OUTLETEXTENDING LATERALLY THROUGH SAID CASING AND COMMUNICATING WITH THE UPPEREND OF SAID FIRST ANNULAR SPACE WHEREBY THE FLUID TO BE HEATED CAN BEDISCAHRGED FROM THE CASING; A PLURALITY OF TUBULAR MEMBERS SECURED TOAND PENETRATING THE OUTER SLEEVE AT THE UPPER END THEREOF AND EXTENDINGLATERALLY THEREFROM; A FLANGED RING SECURED TO SAID TUBULAR MEMBERS ANDINCLUDING A PORTION WHICH EXTENDS OUTWARDLY AND UPWARDLY TO BE SECUREDBETWEEN THE CAP AND THE CASING WHEREBY THE SLEEVES ARE SUPPORTED ON THECASING AND THE SLEEVES CAN BE REMOVED FROM THE CASING AND THE CAP ISREMOVED; AND A RING OF HEAT INSULATION MATERIAL OF SUBSTANTIALLYTRIANGULAR CROSS-SECTION DISPOSED BETWEEN SAID LINING AND SAID PORTIONOF SAID FLANGED RING ABOVE SAID TUBULAR MEMBERS TO PREVENT OVERHEATINGOF THE JOINT BETWEEN THE CASING AND THE CAP.